why do not have a " export uv layout option"
If "Export UV Layout" menu is not available, check if the addon is enabled:


In "File" -> "User Preferences...",
In Tab "Add-ons",
Select the "Import-Export" category,
Check that "Import-Export: UV Layout" is enabled,
If not, enable it by checking the corresponding box (be sure to save your change by clicking "Save User Settings" button


Normally, the option is now available in the UVs menu.